Hydraulic pilot reamer for directional drilling



Aug. 3, 1954 w. G. JAMES 2,585,431

HYDRAULIC PILOT BEAMER FOR DIRECTIONAL DRILLING 'Filed oct. 1, 1951 Patented Aug. 3, 1954 HYDRAULIC PILOT BEAMER FDR DIRECTIONAL DRILLING William G. James, Denver, Colo., assignor to Eastman Oil Well Survey Company, Denver, Colo., a

corporation of Delaware Application October 1, 1951, Serial No. 249,082

Claims.

apparatus and particularly to apparatus for enlarging bore holes which have been drilled off at an angle to another bore hole.

In the directional drilling and side-tracking of bore holes, it has become the general practice to drill a deflected or offset bore which extends at an angle from the main well bore. Because this deflected bore is of a smaller diameter than the diameter of the main well bore, it is sometimes diicult to follow up with a reaming operation. The deflected or oiset bore is of a smaller diameter because the drilling is performed off of the face of a whipstock or by means of some kind of deflecting tool which must obviously be under gauge as compared to the main well bore. It always is the practice to enlarge the smaller deiiected bore by means of a reamer type of drill bit, and pilot such as those now in general use. Because of the small diameter of the deflected bore, difficulty has been experienced in causing the pilot of the reamer to enter said bore.

One of the objects of this invention is to provide improved means including a reaming bit and pilot therefor for enlarging deflected bore holes.

Another object is to produce a reaming bit and pilot therefor for directional drilling which will be simple in construction, rugged, easily conditioned for operation, including the placing of the pilot in the deflected bore, and eiicient in use.

A further object is to produce a directional drilling apparatus for enlarging deflected bore holes which will permit the efficient use of a diamond drill bit to accomplish the enlarging.

Still a further object is to produce an enlarging drill bit and a pilot therefor which will be so combined that no relative longitudinal movement therebetween will occur during drilling operations, yet the pilot can be easily deiiected laterally relative to the axis of the drill bit so that entry into the bore to be enlarged can be eiliciently and quickly accomplished.

A more specific object is to produce an improved permanent type of connection between a pilot and drill bit employable in enlarging a deflected bore hole and particularly one of the type which will permit the pilot to be deflected by hydraulic action to a position when the hole to be enlarged can receive the pilot by the rotation of the drilling stem.

Other objects of my invention will become apparent from the following description taken in connection with the accompanying drawings showing a preferred embodiment.

In the drawing:

Figure l is a view of a well bore illustrating the improved drill bit and pilot when lowered into the bottom of a well bore having the smaller bore previously drilled off therefrom at an angle;

Figure 2 is a view similar to Figure 1, but illustrating how the pilot has been deected to one side of the well bore by the reaction of discharged fluid and then caused to be moved into the smaller deflected bore so that enlarging of this latter bore can be efficiently accomplished.

Figure 3 is a longitudinal sectional view, with some portions in full lines, showing details of the improved bit and pilot member.

In the drawings, the numeral Il! designates a main well bore which has been drilled in the usual manner. A deflected or angular well bore I I which has a diameter smaller than the diameter of' the main well bore extends of from the bottom I2 of said main bore and is ordinarily disposed at an angle thereto. The smaller bore I I has been formed by means of a drill bit which has been deflected off of a whipstock or other deiiecting tool or it may have been formed by means of any of the well known knuckle joint deflecting tools which are in general use.

After the smaller deflected bore II has been formed, it is necessary that this bore be enlarged to substantially the same diameter as the well bore It, and to accomplish this my improved drill bit and pilot member therefor is employed. It will be attached to the lower end of the drill pipe or stern S after said pipe has been withdrawn following the drilling of the smaller deflected bore I I. The preferred structure of the improved bit and pilot member is shown in Figure 3.

The bit B has a body i3 provided with an axial bore I4. At the lower end of the body there is provided the cutting means for the bit which is preferably of the so-called abrasive type, commonly known as a diamond bit, although other types of cutting means can be employed such as the common rock type with cutter teeth. The lower end of the body carries a moulded matrix I5 having small particles of abrasive material of extreme hardness embedded therein, such as chips of diamonds, Sapphires, carborundum, etc., said particles being indicated by the numeral I6.

The upper end of the bore of the bit body is provided with internal threads I'I whereby it can have secured to it a hollow connector member C for connecting the bit to the drill pipe or stem S. lt will be noted that the connector member C has external threads I8 on its lower end for cooperation with the threads Il on the bit body and at its upper end the connector has internal threads I9 for cooperation with the threaded end of the lowermost drill pipe section 20 of the drill pipe or stem S. The bore I4 of the bit body above the bit cutting surface is formed to provide a portion of a conical surface 2i exposed toward the upper end of the bit. At the lower end of the bore 22 in the hollow connector member C, a similar conical surface is formed which is indicated at 23. When the connector C is threadedly connected to the bit B, these two conical surfaces 2l and 23 cooperate to provide a receiving socket for a ball end on the pilot member P.

The pilot member P is an elongated member, circular in cross section, being approximately three feet in length in the particular drilling apparatus shown. The lower end which is below the bit is smooth and rounded, as indicated at 24, and at the upper end the external surface is provided with a spherical surface or ball 25. This ball is received in the socket formed by the two conical surfaces on the bit and connector. Thus, the pilot can have universal movement with respect to the bit. The axial bore lll in the bit at the matrix is iiared downward somewhat from the lower end of the conical surface. The pilot will be of smaller diameter than the flared part of the bore so that the lower end of the pilot can swing in all directions away from the longitudinal axis of the bit. This movement will be limited by the extent of ilare of the bit bore l 4. The pilot is incapable of movement axially relative to the bit because of its permanent connection with the bit and connector by the ball 25.

The pilot member has a longitudinally extending passage 26 therein. The upper end of this passage is open and communicates with the connector bore 22 and by it with the drill pipe or stem S. The lower end of the passage 2t is closed in its axial direction, but near the end of the pilot there is provided an outlet 2l extending through the side wall of the pilot in a radial direction. With this outlet, fluid can be discharged laterally toward the wall of the well bore and the reaction of this discharge jet will establish a force acting on the pilot to swing it in the direction opposite the direction of uid discharge. The fluid, commonly known as drilling mud, will be pumped from the top of the well flowing down through the drill pipe or stem S, the connector C and into the pilot passage. After its discharge it will flow back up to the top of the well outside the drill pipe or stem.

In order that fluid may also flow to the cutting surface of the bit to keep it cool and to also wash away cuttings, the pilot at the ball has passages 28 and 29 extending outwardly and downwardly from the passage 25 in the pilot to thereby direct fluid outwardly and onto the abrasive cutting surface of the bit.

In using my improved bit and pilot, it will be assembled as shown in Figure 3 and connected to the lower section of the -drill stem. After it is lowered to touch the bottom I2 of the main bore i il, as shown in Figure l, it will be raised slightly, say two inches, and then the circulation of fluid will be started. This will cause a discharge from the outlet 2 adjacent the end of the pilot and the reaction therefrom will throw the lower end of the pilot over against the side wall of the main bore lll. The direction of movement will be opposite the direction of discharge of fluid since the reaction force causes the movement. Now the drill pipe or stem will be very slowly rotated a step at a time thereby causing the lower end of the pilot to move around the side wall at the bottom l2 of the main bore. During this step rotation the drill stem will be lowered and raised in a poking action to iind the entrance to the smaller bore H. When the drill stem moves downwardly more than the raised two inches it will be known that the pilot has entered bore H. The pilot will turn with the drill stem, notwithstanding the ball and socket connection, as friction will be present and also fluid under pressure will be acting on the upper end of the pilot to increase the normal friction. After the pilot slips into the smaller bore Il, the drill pipe or stem S will be rotated at a drilling rate and lowered further. The rotating reamer bit will then begin to shave the lower end of bore I0 till it reaches the entrance to bore ll at which time reaming thereof will commence. The diamond bit will perform rapid reaming and there will be circulation ci" uid over its cutting surface. Roaming can be continued until sufficient depth is obtained in the smaller bore. The pilot will move ahead of the bit and insure that the bit will enlarge the bore l l and be properly kept in the bore. The bore H will be enlarged downwardly until the lower end of the pilot hits the bottom of the bore. After the bore i l is enlarged, the drill pipe or stem will be pulled out of the bores li and l@ and the bit and pilot replaced by the usual drilling bit, which will then be employed to continue to drill the deiiected enlarged bore l l downwardly in the angular direction with respect to the main bore lil.

Being aware of the possibility of modifications in the particular structure shown by way of example as embodying my invention, all without departing from the fundamental principles of the invention, I desire it to be understood that the scope of said invention is not to be limited in any manner except in accordance with the appended claims.

What is claimed is:

l. A drilling apparatus attachable to the lower end of a drill pipe for enlarging an earth bore which has been previously drilled off at an angle from another larger bore, said apparatus comprising a drill bit having a bore and carrying cutting means at its lower end, an elongated pilot member having a smooth lower end, and means for connecting the upper end of the pilot member to the bit at a point above the bottom of the bit, said connecting means permitting swinging at the connection and movement of the lower end of the pilot member laterally out of alignment with the bit axis, said pilot member having a longitudinal passage therethrough with its upper end communicating with the bore of the bit and its lower end above the end of the pilot member being provided with an outlet for discharging fluid laterally of the longitudinal axis of the passage, said hollow part of the drill bit below the connecting means for the pilot being of such larger size than the pilot member as to allow the pilot member to be deilected by the discharge of fluid through the outlet at its lower end to a position where it will be adjacent the wall of .the larger bore whereby turning of the drill stem can result in the lower end of the pilot also being moved and placed at the entrance end of the smaller bore which is to be enlarged by the drill bit.

2. A drilling apparatus attachable to the lower end of a drill pipe for enlarging an earth bore which has been previously drilled off at an angle from another larger bore, said apparatus comprising a drill bit having a bore and carrying cutting means at its lower end, an elongated pilot member having a smooth lower end, means for connecting the upper end of the pilot member to the bit at a point above the bottom of the bit, said connecting means permitting swinging at the connection and movement of the lower end of the pilot member laterally out of alignment with the bit axis, said pilot member having a longitudinal passage therethrough with its upper end communicating with the bore of the bit and its lower end above the end 0f the pilot member being provided with an outlet for discharging fluid laterally of the longitudinal axis of the passage, said hollow part of the drill bit below the connecting means for the pilot being of such larger size than the pilot member as to allow the pilot member to be deflected by the discharge of fluid through the outlet at its lower end to a position where it will be adjacent the wall of the larger bore whereby turning of the drill stem can result in the lower end of the pilot also being moved and placed at the entrance end of the smaller bore which is to be enlarged by the drill bit, and means for discharging fluid coming through the bore of the bit toward and on the cutting means of the bit.

3. A drilling apparatus attachable to the lower end of a drill pipe for enlarging an earth bore which has been previously drilled off at an angle from another larger bore, said apparatus comprising an annular drill bit carrying cutting means at its lower end, a hollow connecting member attached to the upper end of the bit, and an elongated pilot member having a smooth lower end, means for connecting the upper end of the pilot member to the bit at a point in its bore above the cutting means, said connecting means permitting movement of the lower end of the pilot member laterally out of alignment with the bit axis, said pilot member being of no greater diameter throughout its length to the connection than the drilled angular earth bore and having a longitudinal passage therethrough with its upper end communicating with the bore of the connecting member and its lower end above the end of the pilot member being provided with an outlet for discharging fluid laterally of the longitudinal axis of the passage, said hollow part of the drill bit below the connecting means for the pilot being of such larger size than the pilot member as to allow the pilot member to be deilected by the discharge of fluid throughthe outlet at its lower end to a position where it will be adjacent the wall of the larger bore whereby turning of the drill stem can result in the lower end of the pilot also being moved and placed at the entrance end 0f the smaller bore which is to be enlarged by the drill bit.

4. A drilling apparatus attachable to the lower end of a drill pipe for enlarging an earth bore which has been previously drilled off at an angle from another larger bore, said apparatus comprising an annular drill bit carrying cutting means at its lower end, a hollow connecting member attached to the upper end of the bit, said drill bit and the connector having associated with their bores cooperating surfaces forming a ball receiving socket, above the cutting means of the drill bit, and an elongated pilot member provided with a smooth lower end and with a ball portion at its upper end mounted in between the spherical surface portions, said pilot member being of no greater diameter throughout its length to the connection than the drilled angular earth bore and having a longitudinal passage therethrough with its upper end communicating with the bore of the connecting member and its lower end above the rounded end of the pilot member being provided with an outlet for discharging iluid laterally of the longitudinal axis of the passage, said hollow part of the drill bit below the socket being of such larger diameter than the pilot member as to allow the lower end of the pilot member to be deflected by the discharge of uid through the outlet at its lower end to a position where it will be adjacent the wall of the larger bore whereby turning of the drill stem can result in the lower end of the pilot also being moved and placed at the entrance end of the smaller bore which is to be enlarged by the drill bit.

5. A drilling apparatus attachable to the lower end of a drill pipe for enlarging an earth bore which has been previously drilled off at an angle from another larger bore, said apparatus comprising an annular drill bit carrying an annular cutting means of the abrasive type at its lower end, a hollow connecting member attached to the upper end of the bit, said bit and connector having surfaces in their bores forestablishing a ball receiving socket above the bit cutting end, and an elongated pilot member provided with a rounded lower end and with a ball portion at its upper end mounted in between the spherical surface portions, said pilot member being of no greater diameter throughout its length to the connection than the drilled angular earth bore and having a longitudinal passage therethrough with its upper end communicating with the bore of the connecting member and its lower end above the end of the pilot member being provided with an outlet for discharging fluid laterally of the longitudinal axis of the passage, said hollow part of the drill bit below the socket being of such larger diameter than the pilot member as to allow the lower end of the pilot member to be deflected by the discharge of uid through the outlet at its lower end to a position where it will be adjacent the wall of the larger bore whereby turning of the drill stem can result in the lower end of the pilot also being moved and placed at the entrance end of the smaller bore which is to be enlarged by the drill bit, said pilot member also being provided with passage means in its wall for directing fluid from the longitudinal passage outwardly to the cutting means of the bit.

References Cited in the lle of this patent UNITED STATES PATENTS Number Name Date 1,902,174 Lewis Mar. 21, 1933 2,167,194 Anderson July 25, 1939 2,249,732 Green July 22, 1941 2,300,016 Scott et al. Oct. 27, 1942 

